Specifically the CRS305-1G-4S+IN, a great little switch and can run either RouterOS or SwOS. Pair with some decent copper DAC twinax from fs.com and you're all set, the only problem is reliable access to < $200 NIC cards that doesn't require eBay.
The selection of 10GB cards has really improved relatively recently. Search Amazon for "10gb network card" and you'll see lots of choices for around $100 USD.